Presence of a receptor for albumin on individual hbsag polypeptides and on hbsag produced by a hepatoma cell line

Abstract

The receptors for polymerized (P) human (Hu) serum albumin (SA) present on intact hepatitis B surface antigen (HBsAg) have been shown to be associated with the major HBsAg polypeptides, as well as HBsAg produced in vitro by a hepatoma cell line. These observations demonstrate that the albumin receptors are virus-specific. Two laboratories [Neurdth and Strick, 1979; Imai et al, 19791 recently reported that the 22-nm particles representing purified preparations of hepatitis B surface antigen (HBsAg) contain a receptor for polymerized (P) human (Hu) serum albumin (SA). Imai et a1 [I9791 showed that this receptor was associated with HBsAg derived from serum positive for e antigen (HBeAg) and that the receptor was protein in nature. More recently, O'Neill [1979] reported that the binding of HBsAg to P-HuSA was temperature-dependent, because binding decreased as the temperature was raised above room temperature. In addition, he reported that this interaction did not appear to depend on the antigenic subtype of HBsAg. In the present study we have examined two of the major polypeptides derived from purified HBsAg for the presence of P-HuSA receptors. In addition, we have tested whether these receptors are associated with HBsAg particles produced by a hepatoma cell line [Alexander et al, 19781. P22 and P68, respectively, were derived from purified preparations of HBsAg. The HBsAg complement-fixing titer of the original plasma pool from which the HBsAg Two polypeptides with molecular weights of 22,000 and 68,000 daltons, termed

Failure to detect polyalbumin-binding sites on the woodchuck hepatitis virus surface antigen: implications for the pathogenesis of hepatitis B virus in humans

“…Polyalbumin-binding activity was not observed for the major polypeptides of HBsAg or WHsAg (P24/GP27). This has been reported for hepatoma-derived HBsAg, which is composed only of P24 and GP27 (13,15). Particle binding could therefore be explained by sites formed from multimers of these polypeptides.…”

“…Species-specific PABSs have been demonstrated for HBV (1,10,12,13,15,(21)(22)(23)(24)(25)(26)38), but their putative role in pathogenesis and disease is controversial (19,20,23). The PABSs are specific for HSA polymerized by glutaraldehyde but not by other means (e.g., aging, heat treatment, or carbodiimide crosslinking) (19,38).…”

“…Therefore, the woodchuck and WHV are currently being investigated as a model for HBV-induced liver disease. Binding sites for polymerized human albumin have been demonstrated for the HBV virion (1, 26), the 22-nm forms of hepatitis B surface antigen (HBsAg) (10,12,15,22,25), and one or more of the constituent polypeptides (13,21,23,24,38). The polymerized albumin-binding sites (PABSs) were found to correlate with the presence of markers of active virus replication (HB e antigen [HBeAg]) and have been proposed to function in species-specific virus attachment to hepatocytes and thus mediate virus infectivity (18,19,23,37).…”

Interactions between hepatitis B virus and polymeric human albumin I. Production of monoclonal anti‐idiotypes (anti‐anti‐polymeric human albumin) which recognize hepatitis B virus surface antigen

“…While the existence of a liver receptor for polyHSA has never been clearly demonstrated, the ability of polyHSA to bind HBsAg has been documented by several investigators. The question to which HBsAg protein polyHSA is binding is still controversial [9,[11][12]. Our data showed that both anti-Id react with the major 24-kDa protein of the antigen as well as with its glycosylated form.…”

Human Serum Albumin and the Enigma of Chronic Hepatitis Type B

“…It is well known that parasites evade the immune response by the acquisition of preformed host antigens such as red cell glycoproteins, major histocompatibility (MHC);antigens or irhmiinoglobulins [12]. Like the filarial nematode Wuchereria bancrofti [30], hepatitis B virus (HBV) as well as hepatitis B surface antigen (HBsAg) particles [lr" 23,24,32,37,40,44,53] have been sbown to interact with host serum albumin. The recruitment of human serum albumin (HSA) is accomplished by the acquisition of receptor structures for polymerized HSA (pHSA) on the outer coat of HBV, coded for by the pre-S region of the HBV genome [29,39].…”